Standing in the middle of a crowd of his new colleagues in the cafeteria of the old Facebook building, Tyler Shultz listened to an emotional speech Elizabeth was giving. She was talking about her uncle's premature death from cancer and how an early warning from Theranos's blood tests could have prevented it. That was what she had spent the past ten years tirelessly working toward, she said teary-eyed, her voice catching: a world in which no one would have to say goodbye to a loved one too soon. Tyler found the message deeply inspiring. He had started working at Theranos less than a week earlier, after graduating from Stanford the previous spring and taking the summer off to backpack around Europe. There had been a lot to absorb in the space of a few days, not least of which was the news Elizabeth had called this all-employee meeting to announce: the company was going live with its technology in Walgreens stores.

Tyler had first met Elizabeth in late 2011 when he'd dropped by his grandfather George's house near the Stanford campus. He was a junior then, majoring in mechanical engineering. Elizabeth's vision of instant and painless tests run on drops of blood collected from fingertips had struck an immediate chord with him. After interning at Theranos that summer, he'd changed his major to biology and applied for a full-time position at the company.

His first day at work had been filled with drama. A woman named Anjali who headed the immunoassay team had quit, and a group of employees had gathered in the parking lot to say goodbye to her. Word was that Anjali and Elizabeth had had a big falling-out. Then, three days later, Tyler had been informed that the protein engineering group he'd originally been assigned to was being disbanded and everyone was being moved to the undermanned immunoassay team to help out. It was all a bit chaotic and confusing, but Elizabeth's stirring speech made his budding concerns melt away. He left the meeting energized and motivated to work really hard.

A month into the job, Tyler met a new hire named Erika Cheung. Like Tyler, Erika was a newly minted college grad who'd majored in biology, but that was about all they had in common. With his dirty blond hair and famous grandfather, Tyler was a product of the establishment, while Erika came from a middle-class mixed-race family. Her father had emigrated to the United States from Hong Kong and worked his way up from package handler to engineering manager at UPS. She'd spent large stretches of her youth homeschooled.

Tyler and Erika competed to see who could get to $600 first -- the threshold beyond which the company had to report the payments as compensation to the IRS. One weekend, Theranos was looking for more volunteers, so Tyler recruited his four housemates to come give blood with him. They used their combined loot --$250-- to buy beer and burgers and threw a party that evening at the ramshackle house they rented a few blocks away.

Despite their very different backgrounds, Tyler and Erika became fast friends. Their job on the immunoassay team was to help run experiments to verify the accuracy of blood tests on Theranos's Edison devices before they were deployed in the lab for use on patients. This verification process was known as "assay validation." The blood samples used for these experiments came from employees and sometimes from employees' friends and family members. To encourage employees to give blood, Theranos paid them $10 per tube. That meant you could make as much as $50 in one sitting.

The first thing that dampened Tyler's enthusiasm for working at Theranos was seeing the inside of an Edison. During his internship the previous summer, he hadn't been allowed near one, so his anticipation was high when a Chinese scientist named Ran Hu showed him one of the machines with its black-and-white case removed. Standing next to Tyler was Aruna Ayer, his supervisor. Aruna was just as curious as he was: in her previous role as head of the protein engineering group, she had never seen an Edison either. As Ran did a quick demonstration, Tyler and Aruna weren't sure what to think. The device seemed to consist of nothing more than a pipette fastened to a robotic arm that moved back and forth on a gantry. Both had envisioned some sort of sophisticated microfluidic system. But this seemed like something a middle-schooler could build in his garage.

Soon, there were other things that began to trouble Tyler. One type of experiment he and Erika were tasked with doing involved retesting blood samples on the Edisons over and over to measure how much their results varied. The data collected were used to calculate each Edison blood test's coefficient of variation, or CV. A test is generally considered precise if its CV is less than 10 percent. To Tyler's dismay, data runs that didn't achieve low enough CVs were simply discarded and the experiments repeated until the desired number was reached. It was as if you flipped a coin enough times to get ten heads in a row and then declared that the coin always returned heads. Even within the "good" data runs, Tyler and Erika noticed that some values were deemed outliers and deleted. When Erika asked the group's more senior scientists how they defined an outlier, no one could give her a straight answer. Erika and Tyler might be young and inexperienced, but they both knew that cherry-picking data wasn't good science. Nor were they the only ones who had concerns about these practices. Aruna, whom Tyler liked and respected, also disapproved of them and so did Michael Humbert, a jovial German scientist Tyler had befriended.

In a tone that implied she did not, Ran replied, "I'll let you decide for yourself."

When its case was back on, the Edison did sport a touchscreen software interface, but even that was a letdown. You had to pound on the screen's icons to get it to work. Tyler and some other members of the group joked that Steve Jobs would have rolled over in his grave if he had seen one of them. Tyler felt a wave of disappointment wash over him but beat it back by telling himself that the 4S, the next-generation device he had heard was in the works, was probably much more intricate.

Trying to keep an open mind, Aruna asked, "Ran, do you think this is cool?"

Erika and Tyler thought Theranos was also being misleading about the accuracy of other Edison tests, such as a test to measure vitamin D. When a blood sample would be tested on an analyzer made by the Italian company DiaSorin, it might show a vitamin D concentration of 20 nanograms per milliliter, which was considered adequate for a healthy patient. But when Erika tested the same sample on the Edison, the result would be 10 or 12 nanograms per milliliter -- a value that signified a vitamin D deficiency. The Edison's vitamin D test was nonetheless cleared for use in the clinical lab on live patient samples, as were two Edison thyroid hormone tests and a test to measure PSA, the prostate cancer marker.

One of the validation experiments Tyler helped with involved a test to detect syphilis. Some tests measure the concentration of a substance in the blood, such as cholesterol, to determine whether it is too high. Others, like the syphilis test, provide a yes-or-no answer about whether a patient has a particular disease or not. The accuracy of those tests is gauged by their sensitivity -- the measure of how often they correctly label someone with the disease as positive. Over a period of several days, Tyler and several colleagues tested 247 blood samples on Edisons, 66 of which were known to be positive for the disease. During the first run, the devices correctly detected only 65 percent of the positive samples. During the second run, they correctly detected 80 percent of them. Yet, in its validation report, Theranos stated that its syphilis test had a sensitivity of 95 percent.

In November 2013, Erika was moved from the immunoassay group to the clinical lab and assigned to Normandy, the room downstairs with the lab's Edison machines. During the Thanksgiving holiday, a patient order came in from the Walgreens store in Palo Alto for a vitamin D test. As she had been trained to do, Erika ran a quality-control check on the Edison devices before testing the patient sample.

Quality-control checks are a basic safeguard against inaccurate results and are at the heart of the way laboratories operate. They involve testing a sample of preserved blood plasma that has an already-known concentration of an analyte and seeing if the lab's test for that analyte matches the known value. If the result obtained is two standard deviations higher or lower than the known value, the quality-control check is usually deemed to have failed.

The first quality-control check Erika ran failed, so she ran a second one. That one failed too. Erika was unsure what to do. The lab's higher-ups were on vacation, so she emailed an emergency help line the company had set up. Sam Anekal, Suraj Saksena, and Daniel Young responded to her email with various suggestions, but nothing they proposed worked. After a while, an employee named Uyen Do from the research-and-development side came down and took a look at the quality-control readings.

Under the protocol Sunny and Daniel had established, the way Theranos generated a result from the Edisons was unorthodox to say the least. First, the little finger-stick samples were diluted with the Tecan liquid handler and split into three parts. Then the three diluted parts were tested on three different Edisons. Each device had two pipette tips that dropped down into the diluted blood, generating two values. So together, the three devices produced six values. The final result was obtained by taking the median of those six values.

Following this protocol, Erika had tested two quality-control samples across three devices, generating six values during each run for a total of twelve values. Without bothering to explain her rationale to Erika, Do deleted two of those twelve values, declaring them outliers. She then went ahead and tested the patient sample and sent out a result.

This wasn't how you were supposed to handle repeat quality-control failures. Normally, two such failures in a row would have been cause to take the devices off-line and recalibrate them. Moreover, Do wasn't even authorized to be in the clinical lab. Unlike Erika, she didn't have a CLS license and had no standing to process patient samples. The episode left Erika shaken.

Less than a week later, Alan Beam was chatting nervously in Jurassic Park, the upstairs lab, with a female inspector from the Laboratory Field Services division of the California Department of Public Health. The Theranos lab's CLIA certificate was nearly two years old and up for renewal, which required the lab to pass an inspection. The federal Medicare agency outsourced these types of routine inspections to state inspectors.

Sunny had let it be known that no employee was to enter or exit Normandy during the inspection. The stairs that led to the downstairs room were hidden behind a door that could only be opened with a key card. Alan and other members of the lab interpreted the directive as a clear signal that Sunny didn't want the inspector to inquire about what was behind the door. The inspector spent several hours in the upstairs part of the lab and found some relatively minor problems that Alan pledged to correct promptly. Then she was gone -- unaware that she had missed the part of the lab that contained the company's proprietary devices. Alan didn't know whether to be relieved or angry. Had he just helped hoodwink a regulator? Why was he being put in this position?

In the days following the inspection, Sunny ordered a switch from regular venous draws to finger-stick draws for dozens of the blood tests Theranos was offering in Walgreens stores, not just the four performed on the Edisons. That meant that the system Daniel Young and Sam Gong had jury-rigged with the Siemens ADVIAs would now be used on regular patients. It didn't take long for problems to surface.

Elizabeth and Sunny had decided to make Phoenix their main launch market, drawn by Arizona's pro-business reputation and its large number of uninsured patients, who they believed would be especially receptive to the low prices Theranos offered. So, in addition to its one Palo Alto location, the company had just opened two wellness centers in Walgreens stores in the Phoenix area, with plans for several dozen more. Elizabeth planned to open a second lab in Phoenix, but for now the finger-stick samples collected in the Arizona stores were being FedExed back to Palo Alto for testing. The arrangement was far from ideal: the nanotainers were shipped in coolers, but the coolers heated up when they sat baking in the sun for hours on the airport tarmac. This caused the blood in the little tubes to clot.

In early 2014, Tyler Shultz was moved from the immunoassay group to the production team, which operated downstairs in Normandy. This put him back near Erika and other colleagues from the clinical lab who were processing patient samples on the Edisons and the modified Siemens ADVIAs. There were no physical barriers between the two groups, so Tyler could hear the chatter among the lab associates. Tyler learned from Erika and others that the Edisons were frequently flunking quality-control checks and that Sunny was pressuring lab personnel to ignore the failures and to test patient samples on the devices anyway.

Just as had been the case before the launch when they were still testing employee samples, Alan was also encountering issues with potassium results. The blood in the nanotainers was often pink, a telltale sign of hemolysis, and the potassium results the diluted samples were producing were consistently too high. Some were so high that the only way they could have been accurate was if the patients were dead. The problem got so bad that Alan implemented a rule that no potassium result above a certain threshold could be released to a patient. He pleaded with Elizabeth to pull the potassium test from the Theranos menu. Instead, she sent Daniel Young to try to fix the assay.

A few days later, Tyler found himself mingling with other guests in the living room of George's home, a big light-blue shingled house perched on a hill next to the Stanford campus. George's second wife, Charlotte, was playing host to the festivities. Elizabeth's parents had flown in for the occasion and her younger brother, Christian, was there too. So were Channing Robertson and Theranos board member Bill Perry, who had served as secretary of defense in the Clinton administration.

As he debated what to do, he got a call from his grandfather. George said he was throwing Elizabeth a thirtieth birthday party and he wanted his grandson to come and play a tune for her. Tyler had been playing the guitar since high school and liked to compose his own songs. During his travels the previous summer, he'd played in pubs and on street corners around Ireland. Tyler tried to get out of it by invoking work: his shift on the production team was from 3:00 p. m. to 1:00 a. m., overlapping with the evening party. But George insisted. He'd already made a seating chart and placed his grandson between Channing Robertson and Elizabeth at the dinner table. And he was sure Elizabeth wouldn't mind if Tyler missed work to celebrate her birthday. She wanted him there, he said.

At his grandfather's urging, Tyler played the song he'd hastily composed. He tried not to cringe as he sang its cheesy lyrics, which borrowed from Theranos's "one tiny drop changes everything" slogan. To his horror, he had to play it again a little while later because Henry Kissinger arrived late and everybody thought that he too should hear it. When Tyler was finished, Kissinger, who like George Shultz was in his early nineties, recited a limerick he'd written for the birthday girl. The scene had a surreal quality to it: they were all sitting in a circle in the Shultzes' living room and Elizabeth was in the middle, reveling in the attention. It was as though she were the queen and they were her court, kissing her ring. As awkward as the evening was, it made Tyler feel like he was on friendly enough terms with Elizabeth to speak to her candidly about his concerns. Shortly after the party, he sent her an email asking if they could meet.

Elizabeth invited him to her office. Their meeting was brief, but he had time to raise a few of the issues that bothered him. One of them was the representations Theranos made about the precision of its blood tests: the company claimed that its tests had coefficients of variation of less than 10 percent, but the CVs in many of its validation reports were much higher, he told her. Elizabeth acted surprised and said she didn't think Theranos had made such a claim. She suggested they look at its website together and called it up on her big iMac. A part of the site titled "Our Technology" did prominently advertise a coefficient of variation of less than 10 percent with a catchy green-and-white circular logo, but Elizabeth noted that the smaller print above it specified that the claim only covered Theranos's vitamin D test.

"That doesn't sound right," Elizabeth said. She suggested he go speak with Daniel Young. Daniel would be able to walk him through how Theranos performed its data analyses and clear up any confusion. Over the following weeks, Tyler met with Daniel Young twice. Talking to Daniel could be frustrating. He had a long forehead accentuated by a receding hairline that suggested a big, powerful brain. But it was impossible to know what went on inside that brain. His eyes, behind their wire-rim glasses, never betrayed any emotion.

Tyler conceded her point and made a mental note to check the vitamin D validation data. He then brought up the fact that his own CV calculations often didn't match those he found in the validation reports. By his count, the percentages in the reports were lower than they should be. In other words, Theranos was exaggerating the precision of its blood tests.

During their first meeting, Daniel calmly explained why Tyler's CV calculations were wrong: Tyler was taking into account the six values, or "replicates," generated during each Edison test instead of just the median of those six values. The final result Theranos reported to a patient was the median, so only that number was relevant to CV calculations, he said.

The conversation shifted to the syphilis test and what Tyler felt was its overstated sensitivity. Again, Daniel had a ready explanation: some of the Edisons' syphilis results had fallen into an equivocal zone. Results in that zone hadn't been included in the sensitivity calculation. Tyler remained dubious. There didn't seem to be any predefined criteria for this so-called equivocal zone. It could be widened at will until the sensitivity reached whatever number the company wanted. In the case of the syphilis test, it was so wide that more samples had been deemed equivocal than the Edisons had correctly identified as positive. Tyler asked Daniel if he thought Theranos's syphilis test was truly the most accurate syphilis test on the market, as the company claimed. Daniel replied that Theranos had never claimed to have the most accurate tests.

Daniel may have technically been correct, but Tyler had put his finger on a central weakness of the Edison device: its pipette tips were terribly imprecise. Generating six measurements during each test and then selecting the median was a way to correct for that imprecision. If the tips had been reliable in the first place, there would have been no need for such contortions.

There was something else that was bothering Tyler -- something he'd just gotten wind of from Erika -- and he decided to bring that up too. All clinical laboratories must submit three times a year to something called "proficiency testing," an exercise designed to ferret out labs whose testing isn't accurate. Accredited bodies like the College of American Pathologists send laboratories samples of preserved blood plasma and ask them to test them for various analytes.

After Tyler got back to his desk, he googled the two recent articles that had been published in the press about Theranos and emailed them to Daniel. One of them was Elizabeth's Wall Street Journal interview, which stated that Theranos's tests were "more accurate than the conventional methods" and called that improved accuracy a scientific advance. When they met again a few days later, Daniel allowed that the statements in the Journal piece were too sweeping but argued that they had been made by the writer, not by Elizabeth herself. Tyler found this argument a little too convenient. Surely the writer hadn't made up these claims on his own; he must have heard them from Elizabeth. A faint smile briefly crossed Daniel's lips.

"Well, sometimes Elizabeth exaggerates in an interview setting," he said.

When Sunny had learned of their little experiment, he'd hit the roof. Not only had he put an immediate end to it, he had made them report only the Siemens and DiaSorin results. There was a lot of chatter in the lab that the Edison results should have been the ones reported. Tyler had looked up the CLIA regulations and they seemed to bear that out: they stated that proficiency-testing samples must be tested and analyzed "in the same manner" as patient specimens "using the laboratory's routine methods." Theranos tested patient samples for vitamin D, PSA, and the two thyroid hormones on the Edisons, so it followed that the proficiency-testing results for those four analytes should have come from the Edisons.

During its first two years of operation, the Theranos lab had always tested proficiency-testing samples on commercial analyzers. But since it was now using the Edisons for some patient tests, Alan Beam and his new lab codirector had been curious to see how the devices fared in the exercise. Beam and the new codirector, Mark Pandori, had ordered Erika and other lab associates to split the proficiency-testing samples and run one part on the Edisons and the other part on the lab's Siemens and DiaSorin analyzers for comparison. The Edison results had differed markedly from the Siemens and DiaSorin ones, especially for vitamin D.

At 9:16 a. m. on Monday, March 31, 2014, the email Tyler had been waiting for all weekend landed in his Yahoo in-box -- or rather in the in-box of Colin Ramirez, an alias he had made up to remain anonymous. The email was from Stephanie Shulman, director of the Clinical Laboratory Evaluation Program at the New York State Department of Health. She was responding to a query Tyler had submitted the previous Friday under the cover of his new fictional identity.

Tyler told Daniel he didn't see how what Theranos had done could be legal. Daniel's response followed a tortuous logic. He said a laboratory's proficiency-testing results were assessed by comparing them to its peers' results, which wasn't possible in Theranos's case because its technology was unique and had no peer group. As a result, the only way to do an apples-to-apples comparison was by using the same conventional methods as other laboratories. Besides, proficiency-testing rules were extremely complicated, he argued. Tyler could rest assured that no laws had been broken. Tyler didn't buy it.

Armed with the knowledge that he was correct about his proficiency-testing suspicions, Tyler went to see his grandfather. They sat down together in the dining room of George's big house, and Tyler tried to explain to the former secretary of state the concepts of precision, sensitivity, quality control, and proficiency testing and to show him why he thought Theranos's approach to each was lacking. He also revealed that Theranos was using its proprietary device for only a handful of the more than two hundred blood tests it advertised on its website. And that before samples could even be processed on the device, they had to be diluted with a third-party machine six feet long and two and a half feet wide that cost tens of thousands of dollars.

Tyler had reached out to the New York health department because it ran one of the proficiency-testing programs Theranos had participated in. He still suspected that the way the company conducted proficiency testing was improper and he wanted an expert opinion. After exchanging a few emails with Shulman, Tyler had his answer. In response to a description he gave her of Theranos's practices, she wrote back that they amounted to "a form of PT cheating" and were "in violation of the state and federal requirements." Shulman gave Tyler two options: he could give her the name of the offending laboratory, or he could file an anonymous complaint with New York State's Laboratory Investigative Unit. He chose to do the latter.

George took it all in quizzically. Tyler could tell he wasn't getting through to him, but he needed him to know as both his grandfather and a member of the company's board of directors that he could no longer be a party to what was going on. He told him he planned to quit. George asked him to hold off and to give Elizabeth another chance to address everything. Tyler agreed to do so and tried to set up another meeting with Elizabeth, but her rising public profile made her very busy. She asked him to send her an email with his concerns instead. So he went ahead and typed up a long note that summarized his conversations with Daniel Young and explained why he'd found most of Daniel's answers unconvincing. He even included charts and validation data to illustrate his various points. He closed with:

I am sorry if this email sounds attacking in any way, I do not intend it to be, I just feel a responsibility to you to tell you what I see so we can work towards solutions. I am invested in this company's long-term vision, and am worried that some of our current practices will prevent us from reaching our bigger goals.

That reckless comment and accusation about the integrity of our company, its leadership and its core team members based on absolute ignorance is so insulting to me that had any other person made these statements, we would have held them accountable in the strongest way. The only reason I have taken so much time away from work to address this personally is because you are Mr. Shultz's grandson…

Tyler didn't hear anything back for several days. When the response finally arrived, it didn't come from Elizabeth. It came from Sunny. And it was withering. In a point-by-point rebuttal that was longer than Tyler's original email, Sunny belittled everything from his grasp of statistics to his knowledge of laboratory science. The overall message was that Tyler was too junior and green to understand what he was talking about. Sunny's tone throughout was dripping with venom, but he reserved his sharpest words for the questions Tyler had raised about proficiency testing:

I have now spent an extraordinary amount of time postponing critical business matters to investigate your assertions -- the only email on this topic I want to see from you going forward is an apology that I'll pass on to other people including Daniel here.

Tyler was dumbfounded. Elizabeth was threatening him through his family, using his grandfather to deliver the message. He felt a surge of anger. After hanging up with his mother, he headed over to the Hoover Institution.

He hadn't even made it to his car when his cell phone rang. It was his mother and she sounded frantic.

Tyler decided it was time to resign. He replied to Sunny with a one-sentence email giving his two weeks' notice and offering to leave earlier if he wished him to. A few hours later, Mona, the head of HR, summoned him to her office and informed him that the company had decided he should leave that day. She made him sign some new nondisclosure forms and told him security would escort him out of the building. But no one from security was available to come get him, so Tyler saw himself out.

Tyler told her it was too late. He had already resigned and signed his exit papers.

"Stop whatever you're about to do!" she implored.

"That's not what I mean. I just got off the phone with your grandfather. He said Elizabeth called him and told him that if you insist on carrying out your vendetta against her, you will lose."

George Shultz's secretary showed him to his grandfather's corner office on the second floor of the Herbert Hoover Memorial Building. A lifetime's worth of books lined the shelves. Tyler was still unnerved by Elizabeth's threat but calmly explained to George what had happened. He showed him his email to Elizabeth and Sunny's blistering reply. George asked his secretary to make photocopies of them and to put them in his office safe.

Tyler thought he might be getting through this time, but he wasn't sure. The old man was hard to read. His years as a senior member of the president's cabinet, facing down threats like the Soviet Union at the height of the Cold War, had made him a cipher. He absorbed information but rarely volunteered any. They agreed to meet again for dinner that evening at his grandfather's house. As they parted, George told Tyler, "They're trying to convince me that you're stupid. They can't convince me that you're stupid. They can, however, convince me that you're wrong and in this case I do believe that you're wrong."

Erika knew that Tyler had quit and asked herself if she should do the same. Things in the lab had gotten out of control. In addition to the four original Edison tests, the assay validation team had cleared a hepatitis C test on the Edisons for clinical use. Giving patients inaccurate vitamin D results was one thing, but the stakes got a lot higher when you were testing for infectious diseases.

A patient order for a hepatitis C test had come in and Erika had refused to run the sample on the Edisons. When Mark Pandori had asked her to come talk to him about it, she'd broken down in tears in his office. Erika and Mark had a good relationship and Erika trusted him. Ever since he'd arrived a few months earlier, Mark had tried to do the right thing, including with proficiency testing.

Erika told Mark the reagents for the hepatitis C test were expired, the Edisons hadn't been recalibrated in a while, and she simply didn't trust the devices. So they had devised a plan to run patient samples on commercially available hepatitis kits called OraQuick HCV. That had worked for a while, but then the lab had run out of them. When they'd tried to place an order for a new batch, Sunny had lost his temper and threatened to block it.

Then, that very afternoon, at about the same time Tyler had gotten his mother's frantic call, Sunny had summoned her to his office. He had gone through Tyler's emails and figured out that Erika was the one who had sent him the proficiency-testing results. Their conversation had started out cordially enough, but Sunny had berated her when she'd brought up the quality-control failures in the lab. His parting words had been, "You need to tell me if you want to work here or not."

When her shift was over, Erika went to meet up with Tyler. He suggested she accompany him to his grandfather's house for dinner. If George saw that his grandson wasn't the only employee with misgivings about the way Theranos operated, he might come around. Erika agreed that it was worth a try.

When they got there, however, it quickly became apparent to Tyler that his grandfather's allegiance to Theranos had strengthened in the intervening hours. As the Shultzes' household staff waited on them, Tyler and Erika ran through the list of their concerns, but only George's wife, Charlotte, seemed receptive to what they were saying. She kept asking them in a shocked tone of voice to repeat various parts of their story.

George, on the other hand, was unmoved. Tyler had noticed how much he doted on Elizabeth. His relationship with her seemed closer than their own. Tyler also knew that his grandfather was passionate about science. Scientific progress would make the world a better place and save it from such perils as pandemics and climate change, he often told his grandson. This passion seemed to make him unable to let go of the promise of Theranos.

George said a top surgeon in New York had told him the company was going to revolutionize the field of surgery and this was someone his good friend Henry Kissinger considered to be the smartest man alive. And according to Elizabeth, Theranos's devices were already being used in medevac helicopters and hospital operating rooms, so they must be working.

Tyler and Erika tried to tell him that couldn't possibly be true given that the devices were barely working within the walls of Theranos. But it was clear they weren't making any headway. George urged them to put the company behind them and to move on with their lives. They both had bright futures ahead, he told them. They left the dinner frustrated, with little choice but to follow his advice.

The next morning, Erika quit too. She wrote up a short resignation letter and gave it to Mark Pandori to pass on to Elizabeth and Sunny. It said she disagreed with running patient samples on the Edisons and that she didn't think she and the company shared "the same standards in patient care and quality." After taking a look at it, Mark gave it back to her and recommended she leave quietly without making waves.

Erika thought about it for a moment and decided he was probably right. She folded the letter back up and put it in her backpack. But while processing Erika's resignation in her office a few minutes later, Mona asked if she had taken anything from the company. To show she hadn't, Erika opened her backpack and showed her its contents. Mona spotted the letter inside and confiscated it. She made Erika sign a new confidentiality agreement and warned her against writing anything about Theranos on Facebook, LinkedIn, or any other forum.

"We have ways of tracking that," she said. "We'll see it if you post anything anywhere."